Bale wrapping mechanism

ABSTRACT

A bale wrapping mechanism has a roll holding station and a duckbill provided for clamping one end of the roll of wrapping material, said duckbill being pivotally mounted, via at least a first hinge, to the baling chamber sidewalls, for delivering said wrapping material to said baling chamber by insertion of said duckbill between adjacent rolls of said baling chamber, wherein the wrapping mechanism further has at least a first guiding roll for guiding the wrapping material between said roll holding station and said duckbill, wherein said first guiding roll axis substantially coincides with the first hinge axis.

This application is the US National Stage filing of InternationalApplication Serial No. PCT/EP2014/060856 filed on May 26, 2014 whichclaims priority to Belgian Application BE2013/0367 filed May 27, 2013,each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an agricultural round baler. Morespecifically it relates to an improvement to the wrap dispensing systemthat allows a net wrap to be placed around a formed bale.

BACKGROUND OF THE INVENTION

Agricultural round balers have been used for several decades to collectand bind crop material so as to facilitate the storage of crop materialfor later use. Generally, a mower or mower-conditioner cuts the crop andarranges it in a windrow for drying. Later, an agricultural tractorpulls a baler over the windrow to collect the crop material. The baler'swindrow pickup gathers the cut and windrowed crop and lifts it into thebaling chamber. The baling chamber consists of a pair of opposingsidewalls with a series of belts that rotate and compress the cropmaterial into a cylindrically shaped bale. When the bale has achieved adesired size and density, the operator wraps the bale to ensure that thecylindrical and compact nature of the bale is maintained. There are manywrapping materials and methods of wrapping the bale depending on avariety of factors. Initially, twine was used to wrap the bale. Laternet-wrap and silage sheets were introduced. After the bale is bound orwrapped, it is ejected from the baler for later pickup by the farmer.

As previously mentioned, there are a variety of agricultural roundbalers. A general example of this device is illustrated by the NewHolland Roll-Belt™ Round Baler model number 678 manufactured by NewHolland North America, Inc. Generally, round balers are pulled by anagricultural tractor and receive rotational power from the tractor'spower-take-off shaft positioned at the rear of the tractor. The energyis transmitted to a gearbox positioned on the baler. Some balers alsouse a hydraulic motor and pump arrangement to provide energy to thevarious baler elements such as the various rollers and belts. Aspreviously discussed, a variety of methods are used to wrap the bale.Relatively recently, the use of netting or net-wrap has been introduced.It is desirable for bales to maintain a cylindrical shape, however thishas been especially difficult near the edge of the cylindrical bale. Itis difficult for twine to remain on the edge of the bale as well asmechanically placing the twine in that position. Recently attempts havebeen made to extend a portion of the net-wrap around the edge of theround bale. By allowing a slight portion of the net-wrap to extend overthe edge of the bale, the appearance of the round bale is improved.Furthermore, the bale is afforded additional protection.

The tension that is applied to the net is determining for a fast andoptimal spreading of the net-wrap over the edges of the bale. A tensionthat is too small will typically result in the net not spreading out,but remaining bundled in the centre of the bale. As a result, when ittakes a long time to achieve the optimal tension, a significant amountof net is wrapped in a bundle around the centre of the bale therebyinefficiently using the net material. When the tension is too high, thenet will apply to much tension on the supply system and will preventmovement of the supply system towards the baling chamber. That way, nosupply of net will be possible and the feeding of net towards the formedbale will not occur.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a mechanism forwrapping material around a round bale, wherein the tension of thematerial is controllable in a better way than in prior art mechanisms.

To this end, the invention provides an agricultural round balercomprising a main frame, a baling chamber supported by said main frame,said baling chamber having a pair of opposing sidewalls, and a pair ofstationary, adjacent rolls which are rotationally affixed to saidsidewalls; the baler further comprising means for feeding crop materialinto said baling chamber for forming therein a cylindrical bale having acylindrical portion and a pair of opposing ends; and comprising a balewrapping mechanism comprising a roll holding station provided forholding a roll of wrapping material, the mechanism further comprising aduckbill provided for clamping one end of the roll of wrapping material,said duckbill being pivotally mounted, via at least a first hinge, tothe baling chamber sidewalls, for delivering said wrapping material tosaid baling chamber by insertion of said duckbill between said adjacentrolls of said baling chamber, wherein the wrapping mechanism furthercomprises at least a first guiding roll for guiding the wrappingmaterial between said roll holding station and said duckbill,characterized in that said first guiding roll axis substantiallycoincides with the first hinge axis in such a manner that pivoting saidduckbill has no significant influence in the wrapping material distancebetween the duckbill and the roll holding station.

By aligning the rotation point of the duckbill (the first hinge axis)with a guiding roll, pivoting the duckbill around the rotation pointdoes not influence the tension on the wrapping material. When theduckbill is pivoted, because the wrapping material is guided over theguiding roll that coincides with the hinge point, the length of wrappingmaterial between roll holding station and duckbill remains constant,although the distance between the duckbill and the roll holding stationmight change. As a result, pivoting the duckbill does not result in theduckbill pulling wrapping material out of the roll holding station orpushing back wrapping material to the roll holding station. Since nopulling or pushing back of wrapping material occurs when pivoting theduckbill, the tension is not significantly influenced by the pivoting ofthe duckbill, contrary to prior art systems. This allows the tension tobe controlled more easily.

Preferably, said first hinge connects said baling chamber sidewalls withan intermediary arm that is connected to said duckbill so that saidduckbill is pivotally mounted to the baling chamber sidewalls via saidintermediary arm. The duckbill movement is preferably controlled via anintermediary arm. By designing the intermediary arm in length and form,the movement of the duckbill can be amended and thereby optimized todeliver the wrapping material between the adjacent rolls of the balingchamber.

Preferably, the duckbill is pivotally connected to said intermediary armvia a second hinge, whereby the wrapping mechanism comprises a secondguiding roll, whereby said second guiding roll axis substantiallycoincides with the second hinge axis. By providing a second hinge, asecond degree of freedom is given to the duckbill, to allow a morecomplex movement thereof. Providing the second guiding roll, and guidingthe wrapping material over the first and the second guiding roll, has asa result that rotating around the second hinge also does notsignificantly affect the tension on the wrapping material.

Preferably, a second intermediary arm is pivotally mounted to saidduckbill via a third hinge that is positioned at a distance from saidsecond hinge, which second intermediary arm is further pivotally mountedto said baling chamber sidewalls via a fourth hinge so that movement ofthe duckbill is determined by the first and second intermediary arm. Viathe second intermediary arm, the duckbill can be guided in apredetermined movement, as will be explained with reference to thefigures. The combination of first and second intermediary arm allowsdesigning the wrapping mechanism such that the duckbill follows acomplex movement for delivering the wrapping material between theadjacent rolls.

Preferably, said duckbill comprises a pair of elongate plates that arebiased towards on another to grip said wrapping material therebetween,the plates thereby forming a duckbill body showing a sharp edge at oneend thereof. Via the sharp edge, the wrapping material can be gripped.Furthermore, the sharp edge can be moved in between the adjacent rollsto deliver the wrapping material into the baling chamber.

Preferably, said intermediary arm is connected to said duckbill at anedge opposite to said sharp edge, while said second intermediary arm isconnected to the duckbill at a central zone thereof. Such configurationproves to result in an efficient design for introducing wrappingmaterial in between the adjacent rolls of the baling chamber sidewalls.Furthermore, movement of the duckbill proves to be optimal.

Preferably, the duckbill is movable between an advanced position and aretracted position, whereby the duckbill sharp edge extends between theadjacent rolls to deliver the wrapping material into the baling chamberin the advanced position. Movement between two extreme positions(advanced and retracted) can be easily controlled. Furthermore themovement can be designed for an optimal delivery in the advancedposition and for an intelligent place-occupation in the retractedposition.

Preferably, the duckbill, in the retracted position, is self-supportingin such a manner that the duckbill remains in the retracted positionwithout external forces being applied. When the duckbill isself-supporting in the retracted position, a power failure in the balerwill not lead to movement of the duckbill out of the retracted position.In the retracted position, the duckbill does not interfere with the balein the baling chamber (in the advanced position, the duckbill isintended to interfere by delivering the wrapping material to the balingchamber to cover the bale). Therefore it is advantageous when theduckbill is self-supporting in the retracted position.

Preferably, the guiding rolls extend substantially parallel to the rollof wrapping material. This allows an easy guidance of the wrappingmaterial over the guiding rolls to the duckbill.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more details with respect to thedrawings illustrating some preferred embodiments of the invention. Inthe drawings:

FIG. 1 shows a cross-section of a round agricultural baler with parts inposition to begin picking up crop material to form a cylindrical bale;

FIG. 2 shows a cross-section similar to FIG. 1, but with parts shown inposition to begin wrapping net material around a completed cylindricalbale;

FIG. 3 shows an embodiment of a bale wrapping mechanism in an advancedposition; and

FIG. 4 shows the bale wrapping mechanism of FIG. 3 in a retractedposition.

In the drawings a same reference number has been allocated to a same oranalogous element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, it is possible to observe the major elementsand general operation of the present invention. Left and rightreferences are used as a matter of convenience and are determined bystanding at the rear of the round baler and facing the forward end inthe normal direction of travel. Likewise, forward and rearward aredetermined by normal direction of travel of the tractor or round baler.Upward or downward orientations are relative to the ground or operatingsurface. Horizontal or vertical planes are also relative to ground.

FIG. 1 illustrates a conventional round baler 1 with the baling chamber24 a ready to receive crop material. The round baler 1 is attached to atractor (not shown) by means of a tongue 4. Rotational power from thetractor's power-take-off shaft (not shown) is transmitted to a gearbox34 via a drive shaft. This is the source of power to operate the roundbaler. It is also possible that a hydraulic motor and pump arrangementmay be used.

The round baler 1 has a main frame 2 supported by a pair of wheels (onlyone shown) 3. A pickup 5 is positioned in front of the wheels 3. Thebaling chamber 24 a is defined by a pair of opposing baling chambersidewalls 24 and a series of rubber belts defining an apron 23. Furtherdefining the bale chamber 24 a is the floor roll 6, starter roll 7 andstationary dimple roll 8 and a sledge assembly 26. The baling chamber 24a has tailgate 12 that pivots about the tailgate pivot 32 to separatethe tailgate 12 from the front portion 39 of the baler 1. The sledgeassembly 26 comprises a pair of sledge arms 33 between which rotatablyextend a lower, pivot roll 9, a middle, stripper roll 10 and an upper,follower roll 11. The assembly is rotatable about an axis whichcoincides with the axis of the pivot roll 9.

The series of rubber belts or apron 23 encircle the sledge follower roll11, drive roll 14, backwrap roll 15, front serpentine roll 16, rearserpentine roll 17, top/front tailgate idler roll 18, top/rear tailgateidler roll 19, middle tailgate idler roll 20, bottom tailgate idler roll21 and nose idler roll 22. The length of the apron 23 is adjusted by apivoting serpentine take up arm 13. The serpentine take up arm 13rotates clock wise (as seen in FIG. 1 when the chamber 24 a is empty andthen in FIG. 2 when the chamber 24 a is full) as the crop materialenters the bale chamber 23 and increases the length of the apron 23 asthe size of the bale 35 increases.

Generally, the tractor pulls the baler 1 over the a windrow ofpreviously cut crop. The pickup 5 inserts the crop between the floorroll 6 and starter roll 7 into the baling chamber 24 a. As more cropmaterial enters the bale chamber 24 a, the serpentine take up arm 14 andsledge assembly 26 rotate clockwise (as viewed in FIGS. 1 and 2) toallow additional crop material to enter the chamber 24 a while ensuringthat proper pressure is maintained on the bale. When the bale chamber 24a is full, the bale wrapping system 30 engages and wraps the bale. Oncethe bale 35 is wrapped, the tailgate 12 raises and ejects the bale fromthe bale chamber 24 a and away from the round baler 1 and tractor.

The bale wrapping mechanism 30 comprises a system for applying wrappingmaterial such as netwrap 41 around a bale by means of a netwrap deliveryassembly 50. The netwrap delivery assembly 50 places the netwrap 41 ontothe cylindrical portion 36 of the bale 35 and preferably over the edgeof the bale so as to cover a portion of each end of the bale. Thenetwrap 41 is stored on a netwrap roll 31 in a roll holding station andis dispensed to a netwrap delivery assembly 50. FIG. 1 shows a prior artassembly 50 that is rotated about a pivot 55 and controlled by anactuator 70. The netwrap delivery assembly 50 comprises a duckbillshowing a sharp edge, that is provided to clamp the wrapping materialfor introduction in the baling chamber.

In the start of a typical baling operation, as seen in FIGS. 1 and 4,the netwrap delivery assembly 50 is withdrawn and held in its retractedposition. When sufficient crop material has entered the baling chamber24 a (as seen in FIG. 2), the actuator 70 is extended, rotating thenetwrap delivery assembly 50 so that the duckbill is inserted betweenthe stationary dimple roll 8 and the pivot roll 9. This may be seen inFIGS. 2 and 3.

Netwrap 41 is provided by the netwrap roll 31. Preferably, the netwrap41 is spread by spreader rolls and is clamped by the duckbill.

The bale wrapping mechanism 50 (as seen in FIG. 3) comprises a pair offirst intermediary arms 65 that can be formed as end plates arranged onopposite sides of the baler and extending substantially parallel to thebaling chamber sidewall. The bale wrapping mechanism 50 furthercomprises a duckbill assembly which extends across the width of thebaler between the pair of first intermediary arms 65. In the duck billassembly, the wrapping material 64 is gripped between an upper plate 61that is fixed to the first intermediary arms 65 and a pivoted lowerplate 62 that is spring biased towards the fixed plate 61. Thisconfiguration is also called a duckbill 60. The wrapping material 64passes between the fixed plate 61 and the pivoted plate 62 and isgripped by them. Because the duckbill acts as a one-way clutch, thewrapping material can pass freely through the duckbill 60 when movingtowards the baling chamber but meets with resistance in the oppositedirection.

Each first intermediary arm 65 is mounted to the baling chamber sidewallvia an first hinge and can be connected to a hydraulic actuator (notshown) which acts to pivot the duckbill between the two end positionsshow in FIGS. 3 and 4. The figures show an alternative and preferredembodiment wherein the second intermediary arm 68 is connected to ahydraulic actuator 80. The construction as is shown in FIGS. 3 and 4 issuch that actuating the first intermediate arm 65 via a hydrauliccylinder might not be able to start rotation of the second intermediaryarm 65 in the correct rotational direction. Therefore in the alternativeembodiment, the second intermediary arm 65 is actuated. The wrappingmaterial is preferably guided over a metering roller (not shown).Alternatively, one of the first or second guiding roll (explainedfurther hereunder) can be configured as metering roller. Each of theguiding rolls may be formed near its two axial ends with oppositelyhanded helical formations which act as spreaders to keep the wrappingmaterial taut across the width of the duckbill 60.

The bale wrapping mechanism preferably comprises a cutting mechanism forsevering the wrapping material 64 after a bale has been formed. Thecutting mechanism comprises a knife 61 a, shown in FIG. 4 only but wouldbe included in FIG. 3 also, carried by two arms pivoted about an axisand operated by means of two linking rods which connect the arms to theduckbill through an arrangement schematically illustrated by dashedlines 61 b. In this way, as the duckbill is retracted, this being theposition adopted by the duckbill in between operating cycles of thewrapping mechanism, the knife is raised against a fixed striker plate orshear bar to separate the length of material wrapped around the newlyformed bale from the supply roll.

The bale wrapping mechanism preferably comprises primary and secondarybrake mechanisms shown schematically at 31 a and connected to supplyroll 31 by a mechanical connection 31 b, shown as dashed linesassociated with the supply roll 31. The primary brake mechanismcomprises a brake pad, a lever and a spring and applies a braking forcewhile material is being drawn from the supply roll in order to maintainthe material under tension. The secondary brake mechanism, which variesthe braking as the size of the supply roll changes comprises a roll sizegauge levers, springs and a lever. A braking force is applied to preventany movement of the supply roll between wrapping cycles and a brakerelease lever disengages this braking force whenever the duckbill is notin the advanced position. The supply roll is braked between balewrapping cycle but allows wrapping material to be drawn from the rollwhile it is maintained under tension during the wrapping cycle.

At the end of a wrapping cycle and at the commencement of the next, theduckbill 60 is in the retracted position, in which the knife has beenoperated to sever the wrapping material a short distance in front of theduckbill to leave a loose flat of wrapping material 64 protruding fromthe duckbill 60.

To commence a new wrapping cycle after the next bale has been formed,the hydraulic actuator is operated to rotate the intermediary arms 65,68 into the advanced position (shown in FIG. 3). This advances theduckbill 60 into the gap between the rollers 8 and 9. The protrudingflap of wrapping material 64 is stripped off the duck bill by thestripper roller 8 and introduced into the bale forming chamber. The flapis then gripped by the bale 35 and carried round the periphery of thebale forming chamber. At some stage after it has been sensed that thewrapping material is being drawn from the supply roll 31, the duck billis returned by the intermediary arms 65, 68 to the retracted position(shown in FIG. 4). Once the metering roller (not shown) has sensed thatthe sufficient material has been dispensed to wrap the bale fully, thematerial is severed between the knife and the shear bar, leaving a flapof material 64 protruding from the duckbill 60 in readiness for thefollowing cycle.

The above brief description is believed to suffice for an understandingof working cycle of the baler, but it should be added that, as so fardescribed, the baler and the wrapping mechanism operate in a mannergenerally analogous to that well documented in the prior art referred toabove and further reference may be made to earlier publications for amore detailed description.

FIGS. 1 and 2 are merely added to this application to explain thecontext of a round agricultural baler. In FIGS. 1 and 2, a bale wrappingmechanism according to the prior art is shown. FIGS. 3 and 4 show a balewrapping mechanism according an embodiment of the invention. FIG. 3shows the bale wrapping mechanism in the advanced position where FIG. 4shows the bale wrapping mechanism in a retracted position.

FIGS. 3 and 4 show a roll holding station 72 (schematically shown)provided for holding a roll of wrapping material 31. This roll ofwrapping material 31 supplies wrapping material 64, such as net wrap, tothe baling chamber to cover the bale 35. The wrapping material 64 isintroduced into the baling chamber via an opening that lies between twoadjacent rolls 8, 9. The duckbill 60 is formed to penetrate the openingthereby bringing the wrapping material 64 in the baling chamber. Theduckbill 60, as is explained above, is formed by an upper plate 61 and alower plate 62 that are bias toward another to grip the wrappingmaterial there between. The duckbill 60 thereby forms a sharp edge atone end thereof (in FIG. 3 the sharp end is at the right hand side ofthe duckbill 60).

According to the embodiment as is shown in FIG. 3 and FIG. 4, theduckbill 60 is pivotally mounted to the baling chamber sidewalls viafirst intermediate arm 65 and second intermediate arm 68. As isexplained above, each intermediate arm can be formed as a pair therebyholding the duckbill at the two opposite sidewalls of the balingchamber. The first intermediate arm 65 extends between a first hinge 66and a second hinge 67. The first hinge 66 is connected to the balingchamber side wall while the second hinge 67 is connected to theduckbill. Preferably, the second hinge 67 is connected to the duckbillat an edge thereof that is opposite to the sharp edge. The secondintermediate arm 68 extends between a third hinge 71 and a fourth hinge69. Thereby the third hinge connects the second intermediary arm to theduckbill 60 and is positioned at a distance from the second hinge 67.Preferably the third hinge 71 is located in a central zone of theduckbill 60 (central when the duckbill is considered in cross section asshown in the FIGS. 3 and 4). The fourth hinge 69 connects the secondintermediary arm to the baling chamber side walls.

The bale wrapping mechanism further comprises guiding rolls for thewrapping material 64. In the embodiment of FIGS. 3 and 4, three guidingrolls are provided which coincide with the first hinge 66, the secondhinge 67 and the third hinge 71. As a result of this positioning of theguiding rolls, movement of the duckbill 60 to and from the advancedposition does not result in a pushing or pulling of wrapping material 64from the roll 31. This is the result of the distance between the rollholding station 72 and the first hinge 66 being constant (since thefirst hinge 66 is connected to the baling chamber side wall), and thedistance between the first hinge 66 and the second hinge 67 beingconstant (since the first intermediary arm does not change length), andthe distance between the second hinge 67 and the third hinge 71 (andalso the sharp edge of the duckbill 63) being constant. The wrappingmaterial 64 is guided from the roll holding station 72 to the sharp edge63 of the duckbill 60 over these guiding rolls 66, 67 and 71. Thereby,movement of the duckbill does not influence the length of wrappingmaterial between the roll holding station 72 and the sharp edge 63 ofthe duckbill 60. Because this length does not change, maintaining apredetermined tension on the wrapping material 64 can be achieved easilyby the above described means.

The duckbill 60 and the first intermediary arm 65 and the secondintermediary arm 68 are preferably so designed that the duckbill 60 isself supporting in the retracted position (as is shown in FIG. 4).Thereby being self supported is in this context defined as in almost noneed for an external force to be applied for remaining in its “home”position. As can be seen in FIG. 4, the second, third, and fourth hingeare substantially aligned so that the second intermediary arm extendssubstantially parallel to the duckbill 60 in cross section. Furthermore,the first intermediary arm 65 is in a position where it applies a forceto the second hinge 67 in the direction of the third and fourth hinge.Thereby, the assembly remains in the retracted position without the needfor an external force to be applied. A skilled person will understandthat the self supporting position can be further improved by addingelements that function as an abutment for the duckbill 60 and/or thefirst or second intermediary arm. In the example of FIGS. 3 and 4, onlyone actuator needs to be provided to act on the second intermediary arm68 for moving the duckbill 60 from the retracted to the advancedposition and vice versa.

At least the hinges of which the access coincide with the guiding rolls,are located outside the turning circle of a bale in the baling chamber.Furthermore, these hinges are positioned so that their access arepositioned at a distance from bale contacting elements of the baler. Inthis regard, reference is made to FIGS. 1 and 2 where the access of thenet wrap delivery system 50 intersects with bale contacting roll 10.Such intersection makes it impossible for a guiding roll to coincidewith the hinge access, namely there is no space for mounting the guidingroll. Therefore according to the invention, at least part of the hingesthat coincide with the guiding rolls are positioned at a distance from afully formed bale in the baling chamber. Although this is not shown inthe figures, such configuration is theoretically possible with theduckbill that is only mounted via one hinge to the baling chamber sidewalls.

It will be obvious to those skilled in the art that various changes maybe made without departing from the scope of the invention as defined bythe claims.

The invention claimed is:
 1. An agricultural round baler comprising: amain frame; a baling chamber supported by said main frame, said balingchamber having a pair of opposing sidewalls, and a pair of stationary,adjacent rolls which are rotationally affixed to said sidewalls and apick up for feeding crop material into said baling chamber for formingtherein a cylindrical bale having a cylindrical portion and a pair ofopposing ends; and a bale wrapping mechanism comprising a roll holdingstation provided for holding a roll of wrapping material, the mechanismfurther comprising a duckbill provided for clamping one end of the rollof wrapping material, said duckbill being pivotally mounted, via atleast a first hinge having an axis, to the baling chamber sidewalls, fordelivering said wrapping material to said baling chamber by insertion ofsaid duckbill between said adjacent rolls of said baling chamber,wherein the wrapping mechanism further comprises at least a firstguiding roll having an axis for guiding the wrapping material betweensaid roll holding station and said duckbill, said first guiding rollaxis substantially coincides with the first hinge axis and said firsthinge connects said baling chamber sidewalls with an intermediary armthat is connected to said duckbill so that said duckbill is pivotallymounted to the baling chamber sidewalls via said intermediary arm andwherein the duckbill is pivotally connected to said intermediary arm viaa second hinge having an axis, whereby the wrapping mechanism comprisesa second guiding roll having an axis, whereby said second guiding rollaxis substantially coincides with the second hinge axis and wherein asecond intermediary arm is pivotally mounted to said duckbill via athird hinge positioned at a distance from said second hinge, wherein thesecond intermediary arm is further pivotally mounted to said balingchamber sidewalls via a fourth hinge so that movement of the duckbill isdetermined by the first and second intermediary arm; wherein pivotingsaid duckbill does not significantly alter the wrapping materialdistance between the duckbill and the roll holding station.
 2. Theagricultural round baler according to claim 1, wherein said duckbillcomprises a pair of elongate plates that are biased towards one anotherto grip said wrapping material therebetween, the plates thereby forminga duckbill body showing a sharp edge at one end thereof.
 3. Theagricultural round baler according to claim 1, wherein said firstintermediary arm is connected to said duckbill at an edge opposite tosaid sharp edge, while said second intermediary arm is connected to theduckbill at a central zone thereof between said edge and said sharpedge.
 4. The agricultural round baler according to claim 1, wherein theduckbill is movable between an advanced position and a retractedposition, whereby the duckbill sharp edge extends between the adjacentrolls to deliver the wrapping material into the baling chamber in theadvanced position.
 5. The agricultural round baler according to claim 4,wherein the duckbill, in the retracted position, is lower than in theextended position so that the duckbill remains in the retracted positionwithout external forces being applied.
 6. The agricultural round baleraccording to claim 1, wherein the guiding rolls extend substantiallyparallel to the roll of wrapping material.
 7. The agricultural roundbaler according to claim 1, wherein the first hinge is located so thatits axis lies at a distance from a fully formed bale in the balingchamber.
 8. The agricultural round baler according to claim 1, whereinthe bale wrapping mechanism further comprises a cutting mechanism with aknife for cutting the wrapping material after a bale has been wrapped.9. The agricultural round baler according to claim 1, wherein the balewrapping mechanism further comprises brake mechanisms provided forbraking a supply roll in the roll holding station so that a tension isapplied to the wrapping material.
 10. A bale wrapping mechanism for anagricultural round baler, the wrapping mechanism comprising: a rollholding station provided for holding a roll of wrapping material, aduckbill provided for clamping one end of the roll of wrapping material,said duckbill adapted for pivotal mounting, via at least a first hinge,to sidewalls of the baler, for delivering said wrapping material to saidbaling chamber by insertion of said duckbill between adjacent rolls ofsaid baler, at least a first guiding roll having an axis for guiding thewrapping material between a roll holding station of the baler and saidduckbill, and said first guiding roll axis substantially coincides withthe first hinge axis and said first hinge connects said baling chambersidewalls with an intermediary arm that is connected to said duckbill sothat said duckbill is pivotally mounted to the baling chamber sidewallsvia said intermediary arm and wherein the duckbill is pivotallyconnected to said intermediary arm via a second hinge having an axis,whereby the wrapping mechanism comprises a second guiding roll having anaxis, whereby said second guiding roll axis substantially coincides withthe second hinge axis and wherein a second intermediary arm is pivotallymounted to said duckbill via a third hinge positioned at a distance fromsaid second hinge, wherein the second intermediary arm is furtherpivotally mounted to said baling chamber sidewalls via a fourth hinge sothat movement of the duckbill is determined by the first and secondintermediary arm; wherein pivoting said duckbill does not significantlyalter the wrapping material distance between the duckbill and the rollholding station.